Cast Knight of White Orchid before playing your land for the turn to avoid catching up on land and cutting off your ramp
Theres definitely some cards youd want to upgrade as soon as possible, with characters like Usopp, Jinbe, Nefertari Vivi, and Karoo among the first to go
The simplest answer to this question is that cards that are not only desired but also rare enough to warrant a higher price from lack of supply are worth the most
If you roll the planar die in a Planechase game, you can pay 1 life, but you can't alter the result of the roll
Thunderbreak Regent makes Draconic Roar great
Sapphire Medallion can be particularly strong in multiples, building towards a Capsize-lock endgame (bouncing two or more lands a turn on their end step to keep forward progress going without risking anything)